Elevated and supported roadways offer more construction challenges than standard surface streets and highways. Supported roadways, such as for example, bridges, overpasses, ramps, parking decks and parking garages, are built to include two or more deck sections, each section constructed of concrete. The decks are supported on pillars, typically at the junction of two adjacent deck sections. Gaps are intentionally left between adjacent deck sections to allow for deck movement caused by various factors, such as changes in weather or settling of the pillars over time. The width of a gap may vary from bridge to bridge, and in a bridge having more than one gap, from gap to gap. Each gap is subsequently filled by a joint.
The joints constructed between the decks must also allow for movement of the adjacent decks. Conventional joints are typically made of a different composition than the asphalt surface of the roadway. One type of joint is constructed of aggregate chips and a binder. The mix of chips and binder are placed in a channel cut into an asphalt layer which has been previously applied on top of the concrete decks. The channel is generally centered over a gap between two adjacent decks.